Air door operator

ABSTRACT

A pivotal door is powered towards both open and closed positions by a shaft connected to a gear engaging a pair of rack members connected to double acting air cylinders inturn connected to a solenoid valve which is responsive to switches in the door carpet such that each of the air cylinders assist in both opening and closing the door. The operation of the door operator is buffered by the metering of oil between cylinders for the rack members having pistons thereon.

Unite States Patent 5] Oct. 24, 1972 Hedrick [54] AIR 0R OPERATOR3,447,423 6/ 1969 Henry ..92/68 X 7 Inventor: Lloyd C- Hedrick, 912Washington 3,195,879 7/ 1965 BOl'ld et a1 ..49/264 X Pleasantville, Iowa50225 I Primary Examiner-J. Karl Bell [22] Wed: Sept 1970Attorney-Zarley, McKee & Thomte [2!] Appl. No.: 70,848

[57] ABSTRACT [52] US. Cl. ..49/264, 49/137, 49/ 334, A pivotal door ispowered towards both open and 9/336, 60/52 CD closed positions by ashaft connected to a gear engag- [51 Int. Cl. ..E05i 13/00, E05f 15/04ing a pair of rack members connected to double acting of Search aircylinders intum connected to a solenoid valve 60/52 57; 92/68 which isresponsive to switches in the door carpet such that each of the aircylinders assist in both opening [56] References cued and closing thedoor. The operation of the door operator is buffered by the metering ofoil between cylin- UNITED STATES PATENTS 4 ders for the rack membershaving pistons thereon. 3,040,717 6/1962 Rumsey ..92/68 X 3,056,573 10/1962 Matheson et al. ..92/68 X 9 Claims, 8 Drawing Figures 5 I: w I I /5h 1 I 52 /Z II l I 36 l l I l il 5 l ,2 y 38 2". 4 I I I v a' I 26 1 l I-i I i l "/''/'"i" 'R 4Z5 60 7 7/ l l PATENTEDnm 24 m2 4/? COM/725E501?P5641419 To:

VAL v5 OPE N 2 5 Z MN mm L Wm m A w c M Z u 05 7 m Y mm AIR DOOROPERATOR Automatic door openers heretofore used commercially haveinvolved mechanical gear systems or hydraulically operated door openers.In each case the power train involves a substantially rigid applicationof power to the door during both opening and closing. Consequently, eachoperation of the door results in a sudden jolt to the door, operatingmechanism and wall and floor structure. Additionally, if an object ishit by the door during its operation the forces through the door andoperator are substantial and often times damaging to the door operatormechanism.

The door operator mechanism of this invention is totally air operated atlow pressures and includes two double acting pistons connected to rackmembers engaging opposite sides of a gear on a shaft connected to thedoor such that when the door is either opened vor closed both aircylinders are applying rotational torque to the output shaft to givesmooth operation. If an obstruction is hit by the door the air willpermit the door to yield to the object without damage to the door,operator system or other supporting structure. Moreover, when the dooroperation begins towards either the open or closed positions the actionwill be smooth and fluid-like with a minimum of stress and strain on allmoving parts.

The force transfer vehicle in the door operator system is air which iscompressible as compared to oil in a hydraulic system which operates ina rigid mechanical manner. The pair of rack members operating on thegear result in even pressure on the bearings, gear and shaft eliminatingmany failures that would otherwise occur if the push and pull action onthe gear occurred only on one side.

This invention consists in the construction, arrangements andcombination of the various parts of the device, whereby the objectscontemplated are attained as hereinafter more fully set forth,specifically pointed out in the claims, and illustrated in theaccompanying drawings in which:

FIG. 1 is a fragmentary elevation view showing the air door operator inuse on a door assembly.

FIG. 2 is an enlarged cross-sectional view of the air door operatortaken along line 2 2 and showing the door in two different openpositions.

FIG. 3 is a side elevational view of the air door operator.

FIG. 4 is a cross-sectional view taken along line 4 4 in FIG. 3.

FIG. 5 is a exploded perspective view of the rack and air piston rod.

FIG. 6 is a schematic of the air door operator system; and

FIG. 7 is an electrical schematic of the air door operator system, and

FIG. 8 is an alternate schematic of the air exhaust system.

The air door operator system of this invention is referred to generallyin FIG. 1 by reference numeral 10 and is located in a header 12 above adoorway 14 in a wall 16. A door 18 is pivotally connected to the doorway14 and the header for pivotal movement about the axis of a power shaft20 in the door operator 10. In the entrance to the doorway an opencarpet 22 is provided and on the exit side of the doorway 14 is a safetycarpet 24.

The air door operator system as seen in FIGS. 2, 3 and 4, includes ahousing 26 in the metal channel header 12. The output shaft 20 isprovided with gear teeth 28 on opposite sides thereof separated byreduced radii peripheral surfaces 30. The teeth 28 are exposed intopassageways 32 in which rack members 34 having teeth 36 move inengagement with the teeth 28. A piston head 40 is provided on the outerend of the rack members 34 and has a cross-sectional area close to thecross-sectional area of the passageway 32. The outer edges of the teeth36 are in a plane inwardly offset from the peripheral surface of thepiston 40 adjacent the gear teeth 28 such that the gear can turnsufficiently to provide a 90 opening of the door 18 without the gearteeth 28 hitting the piston 40.

A tapered groove or slot 44 extends from the outer end of thepassageways 32 to the gear shaft 20. An end plate 46 is secured by bolts48 to the housing 26 and includes a passageway 50 for placing thepassageways 32 in communication with each other. An adjustable valve 52is provided for varying the amount of hydraulic oil 54 that is permittedto flow between the rack member passageways 32.

Each of the rack members 34 include a T-shaped slot 56 extendingtransversely of the rack members longitudinal axis to receive a T-shapedmale member 58 on the inner end of a piston rod 60. The piston rods 60extend from double acting air cylinders 62 which include outwardlyextending threaded portions 64 threadably engaging the housing 26 inalignment with the passageways 32 to secure the cylinders 62 to thehousing 26 as best seen in FIG. 4.

The double acting cylinders 62 include pistons 68 having air chambers 70and 72 on opposite sides thereof. A pair of crossover lines 74 and 76interconnect the chamber 70 of one cylinder 68 with the chamber 72 ofthe other cylinder 68 as seen in FIG. 2. It is seen that the pistons 68always move in opposite directions due to their connection with theshaft 20 through the rack members 34.

The crossover lines 74 and 76 are in turn connected to L-members 80 and82, respectively, which are connected to air lines 84 and 86 havingvalves 88. The air lines 84 and 86 are in turn connected to a four-waysolenoid valve 90 in communication with an air compressor 92 through anair regulator valve 94 in an air line 96. An exhaust muffler 98 isattached to the fourway valve 90.

The electrical schematic for the air door operator system is shown inFIG. 7 and includes the four-way solenoid valve 90 controlled by aconventional automatic door opening relay box 100 in turn connected tothe open and safety carpets 22 and 24 respectively.

Thus in operation it is seen that upon stepping on the open carpet 22 aswitch 102 in the carpet is closed thereby energizing the relay box 100which in turn operates the solenoid valve 90 to direct air to oppositeends of the air cylinders 62 to turn the shaft 20 in a counterclockwisedirection as viewed in FIG. 2 to open the door to the 90 position shownby the dash lines. It is seen that air will pass through the line 86 andapply air pressure on the right side of the top piston as viewed in FIG.2 while applying pressure on the left side of the bottom piston throughthe crossover line 76. Simultaneously air is being exhausted from theleft side of the top cylinder in FIG. 2 through the crossover line 74connecting with the line 84 also receiving exhaust air from theright-hand side of the bottom cylinder and this air returns to thefour-way valve to be returned to the atmosphere through the exhaustmuffler 98. When the door 18 is being closed the operation is reversedby the switch 102 returning to its normally open position thus causingthe relay box 100 to actuate the solenoid valve such that air is thendirected through the line 84 to the right-hand side of the bottom pistonin FIG. 2 and the left-hand side of the top piston through the crossoverline 74. Similarly, air is being exhausted from the righthand side ofthe top cylinderand the left-hand side of the bottom cylinder throughthe line 86 to the four-way valve and out the exhaust muffler. Thus itis seen that uniform pressures are applied to both sides of the outputshaft 20 through the rack members 34 to provide a smooth and even torqueto the shaft.

Additionally it is seen that the air drive is buffered by the meteringof oil between the passageways 32 in which the rack members 34 move.Thus, as the top piston 40 on the rack member 34 moves to the left, asseen in FIG. 4, oil is permitted initially to escape rearwardly alongthe rack member due to the enlarged cross-section of the elongated slot44 whereby door movement begins instantly and later comes to a gentlestop as the piston 40 of the top rack member 34 moves further to theleft due to the amount of oil escaping past it becoming less and slowingdown the speed of the door movement towards an open position. When thedoor is being closed the same sequence will occur with regard to theother metering piston thereby providing for instant starting and smoothgentle stopping. It is also seen that the gear and rack members areself-oiled by the circulation of oil and the oil is metered back andforth through the passageway 50 to further smooth out the operation ofthe door operator. If desired, the oil metering may be stoppedcompletely and the operation of the door as well by the closing off ofthe passageway 50 by operation of the valve 52. The speed of the dooroperation may also be controlled by the adjustment of the air flowcontrol valves 88.

The safety mat 24 is seen to include a switch 110 connected to the relaybox 100 and this switch serves to either hold the door open when it isactuated or to hold the door closed in a conventional manner.

The air door operator can operate at very low air pressure on the orderof 40 p.s.i. It is seen that additionally a very little volume of air isused. The inherent resiliency of the air door operator eliminates theneed for springs to wind up or compress to close the door as is requiredby some door operators. The rack and gear assembly are so constructedthat a short stroke will cause a 90 turn of the door. In case of failureof the power system the door may be manually operated by overriding theair pressure. The speed of the door is controlled by the flow controlvalves both as to the rate of air flow on the intake and the exhaust foreach of the cylinders. The metering and dampening or buffering providedby the V-shaped slots in the rack member passageways permit the door tostart instantly and bring the door to a smooth and gentle stop.

The air power for the door makes the operation on recycling muchsmoother such that when the door is on the way closed and another personstarts through the door the air valve switches from the closed to openposition and air will compress preventing the door from opening againwith the sudden violence associated with hydraulic or gear driven doorswhich causes damage and maintenance problems. It is seen that there is auniform load on the bearings and shaft since pressures are even on bothside of the shaft due to the pushing and pulling on the air cylindersconnected to the rack members in turn connected to the output gear.

An alternate air exhaust system is illustrated in FIG.

8 which permits the door to more instantaneously move towards an openposition upon the open carpet 22 being actuated. The air being exhaustedfrom the air cylinder 62 through the conduit 74 and 76 passes through aHumphrey quick dump valve 88A commercially available, into a relativelylarger diameter conduit 149 which is connected to an expansion chamber150 having a needle valve in its outlet conduit 153. Thus the airescapes instantaneously and the door opens without any hesitation uponthe open carpet 22 being stepped upon by a person passing through thedoor. Adjustment of the needle valve 152 controlling the exhaust of theexpansion chamber to the atmosphere will give the fine adjustmentnecessary for a particular door system. The remaining components andoperation illustrated in the schematic of FIG. 6 remain the same sinceany hesitation in the closing of the door will not be objectionable. Theneedle valve 152 allows the exhaust chamber 150 to accumulate air as thedoor moves towards the end of its open movement and thus cushions thedoor at its fully opened position.

I claim:

1. An air powered hydraulic controlled door operator comprising, apivotal door,

a rotatable output shaft connected to said pivotal door for opening andclosing said door,

a gear coupled to said output shaft and rack members engaging said gearon opposite sides thereof,

said gear and rack members are disposed in a housing and said rackmembers each have a piston head moveable in hydraulic fluid cylinders incommunication with each other through a restricted passageway,

a separate double acting air cylinder connected to each of said rackmembers,

an air control system coupled to each of said air cylinders andconnected to an air pressure supply means,

crossover conduits placing opposite ends of said air cylinders incommunication with each other whereby said air control system at timesselectively places opposite ends of said air cylinders in communicationwith said air pressure means and at other times places the other ends ofsaid air cylinders in communication with said air pressure means suchthat at all times each of said air cylinders are operating in oppositedirections and are cooperating to turn said output shaft in a commondirection,

a foot door mat including a normally open switch operatively connectedto said air control system whereby said air cylinders will be operatedto operate said hydraulic cylinders to open said door under air pressureupon said switch being closed and close said door under air pressureupon said switch being opened with said hydraulic cylinders controllingthe opening and closing of the door.

2. The structure of claim 1 wherein each of said rack members includes aloose fitting coupling between it and the piston rod of the associatedair cylinder.

3. The structure of claim 2 wherein said coupling includes a T-shapedelement matingly received in a T- shaped slot such that engagement anddisengagement occurs through lateral movement therebetween relative tothe longitudinal axis of said rack members and piston rods.

4. The structure of claim 1 wherein said control system includes afour-way valve for operatively reversing directions of operation of saidair cylinders.

5. The structure of claim 1 wherein said cylinders each include atapered longitudinally extending slot in the side walls thereofincreasing in size towards said gear for passing a smaller amount offluid past said pistons the farther said pistons are moved from saidgear.

6. The structure of claim 5 wherein said restricted passageway includesan adjustable valve.

7. The structure of claim 6 wherein said gear includes teeth only onopposite sides for engagement with the teeth on said rack members andthe outer plane of the rack teeth is transversely inwardly offset fromthe outer peripheral edge of said pistons adjacent said gear and saidshaft has a smaller radius along the periphery between said teeththereon than the radius to the outer periphery of said shaft teeth.

8. The structure of claim 1 wherein said air control system includes afour-way solenoid valve electrically connected to said switch.

9. The structure of claim 8 wherein said door operator is located in aheader above said door and said output shaft extends downwardly intoengagement with said door.

1. An air powered hydraulic controlled door operator comprising, apivotal door, a rotatable output shaft connected to said pivotal doorfor opening and closing said door, a gear coupled to said output shaftand rack members engaging said gear on opposite sides thereof, said gearand rack members are disposed in a housing and said rack members eachhave a piston head moveable in hydraulic fluid cylinders incommunication with each other through a restricted passageway, aseparate double acting air cylinder connected to each of said rackmembers, an air control system coupled to each of said air cylinders andconnected to an air pressure supply means, crossover conduits placingopposite ends of said air cylinders in communication with each otherwhereby said air control system at times selectively places oppositeends of said air cylinders in communication with said air pressure meansand at other times places the other ends of said air cylinders incommunication with said air pressure means such that at all times eachof said air cylinders are operating in opposite directions and arecooperating to turn said output shaft in a common direction, a foot doormat including a normally open switch operatively connected to said aircontrol system whereby said air cylinders will be operated to operatesaid hydraulic cylinders to open said door under air pressure upon saidswitch being closed and close said door under air pressure upon saidswitch being opened with said hydraulic cylinders controlling theopening and closing of the door.
 2. The structure of claim 1 whereineach of said rack members includes a loose fitting coupling between itand the piston rod of the associated air cylinder.
 3. The structure ofclaim 2 wherein said coupling includes a T-shaped element matinglyreceived in a T-shaped slot such that engagement and disengagementoccurs through lateral movement therebetween relative to thelongitudinal axis of said rack members and piston rods.
 4. The structureof claim 1 wherein said control system includes a four-way valve foroperatively reversing directions of operation of said air cylinders. 5.The structure of claim 1 wherein said cylinders each include a taperedlongitudinally extending slot in the side walls thereof increasing insize towards said gear for passing a smaller amount of fluid past saidpistons the farther said pistons are moved from said gear.
 6. Thestructure of claim 5 wherein said restricted passageway includes anadjustable valve.
 7. The structure of claim 6 wherein said gear includesteeth only on opposite sides for engagement with the teeth on said rackmembers and the outer plane of the rack teeth is transversely inwardlyoffset from the outer peripheral edge of said pistons adjacent said gearand said shaft has a smaller radius along the periphery between saidteeth thereon than the radius to the outer periphery of said shaftteeth.
 8. The structure of claim 1 wherein said air control systemincludes a four-way solenoid valve electrically connected to saidswitch.
 9. The structure of claim 8 wherein said door operator islocated in a header above said door and said output shaft extendsdownwardly into engagement with said door.